Physics, Ph.D. (Ithaca)
Field of Study
The graduate physics program is designed to give students an adequate background in the concepts and techniques of theoretical and experimental physics in preparation for careers at the most advanced level in research or teaching.
Research and Study Opportunities
Theoretical physics -- Condensed Matter. Subjects for study include mesoscopic systems and random matrix theory; collective properties of Bose and Fermi condensates; density functional theory (electronic and liquid) with applications to surface growth and interfaces, defects in solids, matter under extreme conditions, and nanophysics; statistical mechanics and critical phenomena applied to crackling noise, dynamical systems, biological systems, and quasicrystals; inverse problems in protein crystallography; strongly interacting electron physics of magnetism, superconductors, and disordered systems.
Theoretical physics -- Particle and Astrophysics. Physics of extra dimensions and supersymmetry, mechanisms for electroweak symmetry breaking, collider phenomenology; lattice gauge theories; particle astrophysics and cosmology; string theory and its application to cosmology, brane world; field theories; astrophysics; black holes; and general relativity.
Experimental particle physics. Our research uses the Large Hadron Collider (LHC) at CERN, which is the first collider to explore the TeV energy scale, where the Standard Model of particle physics must break down unless new phenomena appear. Cornell is a member of CMS, one of two detector collaborations for elementary particle physics at the LHC. Research topics include mechanisms for electroweak symmetry breaking, including the Higgs mechanism and alternatives, scenarios for physics beyond the Standard Model such as supersymmetry, extra dimensions and new strong interactions, top quark physics, and dark matter. Cornellians are designing online software for the pixel detector, developing strategies for identifying electrons in the electromagnetic calorimeter, writing analysis software capable of handling petabytes of data distributed world-wide, and ensuring that the trigger will successfully pluck new physics out of the huge background of conventional processes. In the next few years, they will also start developing hardware upgrades of the pixels and the trigger.
Accelerator Physics. The electron-positron collider CESR at Cornell University is used as a test-bed for accelerator physics and for X-ray science. Having this large accelerator on campus provides a unique opportunity for students interested in many aspects of accelerator physics. Currently, CESR is testing design concepts for the Linear Collider, which will be the world's largest high-energy physics accelerator. Accelerator research also includes an active program to develop the superconducting radio-frequency cavities needed for the next generation of electron-positron colliders and for future X-ray facilities. The group is also developing a new X-ray facility, the Energy Recovery Linac, for the Cornell campus that offers students the unique opportunity to join a large-scale science project in an early state where many phenomena are still unknown, many parameters need to be computed, and many important decisions are being made.
Experimental condensed matter physics. Subjects of study include nanostructures and quantum transport; superfluid, solid, and supersolid helium; atomic-resolution STM and tunneling spectroscopy; photoemission spectroscopy; high-temperature superconductivity; nanomagnetics; new forms of scanning-probe microscopy; nanomechnanical systems and limits of quantum m
Concentrations by Subject
- experimental physics
- theoretical physics
Application Requirements and Deadlines
Fall, Dec. 15; no spring admission
Most entering students have completed an undergraduate program in physics, including such courses as analytical mechanics, electricity and magnetism, optics and wave motion, electronics, and atomic physics; some advanced undergraduate laboratory work in physics is also expected. Knowledge of linear algebra, differential equations, and vector calculus is essential. Additional study in mathematics is desirable. The quality of undergraduate work and promise for graduate work are weighted more heavily than the extent of undergraduate study in physics and related subjects. Some entering students enroll in one or more undergraduate courses to make up deficiencies.
The Test of English as a Foreign Language (TOEFL) is required for applicants whose native language is not English. Scores must be officially reported by the Educational Testing Service to the Cornell Graduate School (Institution Code #2098, Department Code #76). Scores must arrive by the Dec. 15 deadline. Please note that the minimum IBT TOEFL scores required for consideration are:
- Writing: 20
- Listening: 15
- Reading: 20
- Speaking: 22
An applicant will automatically be granted a TOEFL exemption if he or she studied for two or more years in a country where the primary language is English and the instruction was in English. In addition, international students offered admission as a teaching assistant will also be expected to meet the oral proficiency outlines from ACTFL (American Council on the Teaching of Foreign Languages) at the "Intermediate High" level. This test will be administered at Cornell upon matriculation. A more detailed field brochure is available on request from the Physics Department.
As part of your education, we want to ensure that first and foremost, you know how to “think like a physicist”. This implies that you can synthesize knowledge from different areas, make educated guesses and take your hard-earned course-based knowledge to the next level, where you will apply it and knowledge that you acquire independently or with your mentors and peers to solve problems of interest. That is why we prefer a broad education and course base, and our education will prepare you for a career not just in the specific area that is your dissertation topic but our Ph. D. should prepare you for a career as a professional scientist, with all the flexibility that that implies.
Physicists must also learn how to communicate using written, spoken and presentation skills. You will acquire these skills as part of our course work. For example, Physics 6510, our Advanced Laboratory course has formal materials on how to carry out “Back of the envelope calculations” and a requirement to write lab reports in standard journal (Physical Review Letters) format as well as make a presentation to faculty and peers in a timed format. These formative skills are essential for the practicing Physicist.
Additionally, it is essential that Physicists are aware of ethical issues pertaining to the conduct and dissemination of research, in collaborative research endeavors as well as instances that may arise concerned with the teaching arena. Opportunities to participate in training concerned with ethical issues will be provided and must be completed by all students in their first year. The successful completion of the Responsible Conduct of Research unit online is required of all students.
A candidate for a Ph.D. in Physics is expected to demonstrate mastery of knowledge in the field of Physics, and to synthesize and create knowledge by making an original and substantial contribution to the Field of Physics in a timely fashion.
Proficiencies that are required to be demonstrated by the candidate
Make an original and substantial contribution to the discipline by becoming proficient in the following areas:
- Show your ability to think independent and creativily
- Identify new research opportunities in the field
- The ability to acquire and communicate advanced research skills
- Bring together existing knowledge, identify, and seek out resources, information; apply these to evaluate and apply your own research findings as well as those of others. Apply research findings as appropriate.
- Master and/or innovate research methodologies, and techniques
- Master communication skills for oral and written information exchange
- A commitment to advancing scholarship
- Maintain familiarity with advances in the field
- Engage and communicate findings via professional publications, participation in professional societies, research seminars and other modes of communication
- Support learning—through teaching, collaborative inquiry, mentoring, or demonstration
- Demonstrate professional skills
- Advance ethical standards in the field
- Listen, give, and receive feedback effectively.
Assessment of Learning Outcomes
Exams and assessment are part of the learning process. Formal learning in a classroom environment is assessed in exams that are a part of course work, and could be either take-home, timed in-class exams or term-papers combined with presentation of materials. The Q exam will assess your knowledge of Physics, ability to express yourself and communicate as well as your ability to analyze a problem, break it down into “bite sized components” and work through to obtain an acceptable solution. Examination of your ability to carry out “back of the envelope calculations” is part of the Q exam process. All of these will help faculty assess your success in transitioning from a “knowledge-acquirer” to a practicing physicist who can synthesize and attack complex problems as well create new knowledge by carrying out original research.
The second examination is the Admission to Candidacy Examination (ACE), a comprehensive exam that gauges your knowledge of the field and readiness for independent research. This, too, is an oral examination, but it is administered by the members of your permanent Special Committee. Normally the ‘A’ exam, as it is called, is preceded by one or more written assignments. After passing this exam, usually sometime in your third year, you begin research in earnest. If you have skipped core courses (for example if you took graduate course work as an undergrad) then your Special Committee may ask you questions pertaining to that material. In answering questions, you should also be prepared to demonstrate broad knowledge in your research area as well as communication and presentation skills.
Your third and final exam is the defense of your thesis, the ‘B exam’. It is an oral exam that you take after you complete your Ph.D. thesis research and present it to the members of your committee. The exam covers your thesis and related matters. The B exam also is an “open examination” that will permit the faculty (and your fellow students) to assess the quality of your research and highlights your written, oral and communication skills.